Wood-burning heater for circulating water

Claim 1

A wood burning furnace and boiler comprising: a furnace housing having front and rear walls, opposite side walls, and top and bottom walls; a firebox within said furnace housing and having a grate and spaced side walls, each firebox side wall being spaced from and facing a side wall of said furnace housing; a boiler chamber defined between the furnace housing and the firebox, said boiler chamber including an upper portion and two lower portions defined between said facing side walls on opposite sides of said firebox, said lower portions extending downwardly substantially to said grate, the upper ends of said lower portion being joined to said upper portion; a water preheat chamber comprising an auxiliary jacket connected to the rear wall of said furnace housing in heat transfer relationship therewith, said preheat chamber having an upper wall and a bottom wall; water inlet and distribution means located adjacent the upper wall of said preheat chamber for flowing water into, downwardly and through the preheat chamber, said water distribution means being positioned laterally across said preheat chamber and having a plurality of spaced holes through which water flows downwardly into said preheat chamber; inlet openings communicating the lower end of said preheat chamber and the lower ends of said two lower portions of said boiler chamber for the passage of water from said preheat chamber into said lower portions, said inlet openings being located laterally of said grate; baffle plates joined to the facing side walls of said furnace housing and said firebox in each of said lower portions of said boiler chamber, said baffle plates in each of said lower portions defining an elongated serpentine flow path extending from its associated inlet opening partway toward said upper portion of said boiler chamber so that the water flows through an elongated flow path in each of said lower portions of said boiler chamber and thence into said upper portion of said boiler chamber, said baffle plates being located directly laterally of said grate; and means connected to said upper portion of said boiler chamber for the passage of heated water therefrom.